Important! : bent valves

  1. Established Member Joined: Jan 2010 Posts: 1660 yamaha tzr50/dt125 cars: 1.0i spree
    #1
    my mums cam belt went on the p reg escort the other week but only recently had a chance(could be botherd) to get the head of and look

    basicly long story short
    its bent 4 valves
    3 exhaust and 1 inlet

    how much would i be looking at for new valves
    i can fit my self at collage so just need rought price on vavles
    will also need head gasket set and the inlet gaskets aswell

    thanx guys
  2. Saxperience Post Whore Joined: Mar 2003 United Kingdom (England) Posts: 7064
    #2
    Might be cheaper to get a new head from a breakers!
  3. Frequent Poster Joined: Apr 2010 Shavington Crewe Posts: 828 MK2 Saxo VTR 51 PLATE
    #3
    My old mans van done exactly the same, isit the 1.8 D non turbo? if so id change all the valves and possibly a second hand cam or even a new cam from breakers, cos trust me its annoying when you have to take a head off and strip it down twice.
  4. Established Member Joined: Jan 2010 Posts: 1660 yamaha tzr50/dt125 cars: 1.0i spree
    #4
    not its a 1.3 petrol she thinks im not sure what it is lol doesnt say any were on documents what it is whichis strange

    but the thing is ive never changed valves and mum said if its cheap for valves like 15 each or some thing i can do it so its something new i learn cos we dont get to do that on level 2 at collage i have to wait till level 3
  5. Frequent Poster Joined: Apr 2010 Shavington Crewe Posts: 828 MK2 Saxo VTR 51 PLATE
    #5
    pretty simple really mate, but suggest changing oil stem seals aswell, and also id also suggest changing all valves as when a cambelt goes that engine is spinning over 15x a second for every 1000 RPM and the slightest touch to a valve could send it out, human eye cant tell, engines work on such fine tolerances its not worh the risk mate. and to change valves you will need valve spring depressing tool, it will clamp spring down so you can get the retainer shims off, DONT LOOSE THEM cos they are tiny!!! then release spring carefully and valve will come out through cylinder side of head. obviously ground in all the new valves and then revese the above process.
  6. Regular Poster Joined: Jun 2010 Posts: 279
    #6
    best to buy a head set as you get all of the gaskets and valve stem seals in one kit and the valves are around £12 each as above though dont loose the collets
  7. Frequent Poster Joined: Apr 2010 Shavington Crewe Posts: 828 MK2 Saxo VTR 51 PLATE
    #7
    Quote:
    Originally Posted by sax0gal View Post
    best to buy a head set as you get all of the gaskets and valve stem seals in one kit and the valves are around £12 each as above though dont loose the collets
    Thats the ones, collets
  8. Infrequent Poster Joined: Oct 2010 Bridgend Posts: 231 VTS 2002 - well the Mrs does
    #8
    Quote:
    Originally Posted by H-Unwin View Post
    pretty simple really mate, but suggest changing oil stem seals aswell, and also id also suggest changing all valves as when a cambelt goes that engine is spinning over 15x a second for every 1000 RPM and the slightest touch to a valve could send it out, human eye cant tell, engines work on such fine tolerances its not worh the risk mate. and to change valves you will need valve spring depressing tool, it will clamp spring down so you can get the retainer shims off, DONT LOOSE THEM cos they are tiny!!! then release spring carefully and valve will come out through cylinder side of head. obviously ground in all the new valves and then revese the above process.
    A simple check (DIY) to see if the valves are bent....

    1. With the head and cam removed, spray a small amount of brake cleaner into each intake port. As the valves are shut the port chamber should be sealed. If there is a bend, even the slightest, you will see the brake cleaner leaking past the valve seat.

    2. With the damaged valves you check that the valve guide has been damaged. This can happen when a valve to piston collision has occurred.

    Just for correctness sake, please see the correct terms for the ones used in the previous quote.

    a. retainer shims - these are know correct as 'valve spring collets'. If you lose any at least the parts man will know what you mean.

    b. valve spring depressing tool - known as a 'valve spring compressor'

    Normally when we repair heads after this kind of damage we will vacuum test each valve after to ensure that they are sealing correctly. Another test we would do is known as a 'leak down' test but this has to be performed prior to head removal. Unfortunately, this off the shelf kit is expensive for a one off.

    The decision is yours ultimately whether or not to repair yourself or get a known good replacement head. If you do repair, just make sure that you face the valves faces and seats correctly or you could be wasting your time. There are plenty of guides on the internet on how to do this if you didn't already know.

    I hope this helps....
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  9. Established Member Joined: Jan 2010 Posts: 1660 yamaha tzr50/dt125 cars: 1.0i spree
    #9
    thanx mate realy good help how much would i be looking at for a new head and that i can use vavle spring compressor from a mate so no worrys there
    might just get a new head .. if its around the same price as a diy repair
  10. Infrequent Poster Joined: Oct 2010 Bridgend Posts: 231 VTS 2002 - well the Mrs does
    #10
    All depends on the price really. If all you need is three valves they may be worth repairing it. Heads vary from £50 - £100, occasionally cheaper. By the sounds of it you may be into deciding the beyond economical repair scenario and looking for a head. You need to get some prices really to enable you to make your decision.

    While the head is off, have a good look at the pistons that have hit the valves and make sure that there are no cracks in the crown of them.

    Sorry, I can't be anymore helpful...
  11. Established Member Joined: Jan 2010 Posts: 1660 yamaha tzr50/dt125 cars: 1.0i spree
    #11
    ok will do 2moro when i have chance theres 3 exhaust and 1 inlet bent
    i wil ring scrappy again tomoro for my mums car not mine this time lol